Clonogenic Assay- How resistant are you?

The gene analysis is complete. There is a difference, but does it do?

That is where the clonogenic assay comes in. This might sound familiar and that's good because I have talked about them quite a bit. I never fully explained them (anyone else notice the trend... I'm working on it... I promise). The clonogenic assay is a method of testing radiorestance, or how resistant cells are to radiation. you start off by plating a number of cells on a 6-well plate (its a plastic rectangle with 6 wells just in case that was confusing) and then you irradiate them. For our experiment, we had six 6-well plate (for a total of 36 wells...Wow) and the irradiation treatments were from 0Gy - 10Gy. Duplicates of the three samples of the cell line were on each of the plates. This was completed for all the cell lines 4 times.

Here are the results:

Look at that all three cell lines are there this time. Those lines are cool... what do they do?

Solid question. Here's the answer (well almost): The lines indicate the radioresistance of the cells. On the y-axis, we have graphed the surviving factor, or the ratio of the colonies that have survived after treatment. This is the dependent variable for all you high-schoolers out there (that's me). On the x-axis, we graphed the radiation treatment (that's the independent variable). 

Some of you may be wondering how did all of these numbers were calculated. I appreciate your curiosity and applaud your interest, but to save confusion (and possibly effort) I will leave the explaining to the true experts. To find the full protocol, from irradiateng cells to interpreting data, click the link: http://www.nature.com/nprot/journal/v1/n5/full/nprot.2006.339.html. 

If you have read it, but still have questions, please ask. Now back to the show.

For 22Rv1, the cells that received the FD treatment exhibited greater radioresistance, meaning a greater number of colonies from that sample survived radiation. 

For DU145, there was no difference in radioresistance between the cells that received the two treatments. 

For PC3, the cells that received the SD treatment exhibited greater radioresistance. 

I don't mean to cut the party short, but that's it for the analysis of this data. Now before we begin figuring out what it all means there is one more thing to do. You guessed it! More data to analyze. 

Till next time, my friends!